A few comments made by a hndful of people in the last 2 years lead me to believe that some people can see kundalini energy. My data points include:
1. The physical therapist I credit for my awakening telling me how nice I looked when I really was wearing nothing special.
2. A member of a kundalini discussion group telling me that all my energy was in my stomach area (this was 1+ years ago).
3. A Hindu friend of mine recently telling me that even though it may seem like I am not making progress that I am presently full of light throughout.
4. A guy in my neighborhood who I cycle with one day out of the blue (recently) made a comment that it can take a long time for your light to shine through.
None of these people offered explanations after the comment and at the time some of them were made I was really clueless to what they were saying anyway. So looking back, it seems apparent to me that these people know something I don't and possibly can see physically my spiritual progress.
What comes to my mind are two things. Some people use expressions like "you are full of light" and mean they sense a freshness, positivity and glow around the person without actually seeing any light - they just sense the "good vibes" around the person.
Others have been given the gift of having a third eye (ajna) that is so open they can actually start to see the energies with it. It's possible to see auras, other beings, or just energy as bright or coloured light of different kinds. It is seen as a physical real light, but the seeing comes from the third eye. It's possible to train that ability.
I sometimes spontaneously see a glowing field around persons or objects. Started happening during the few qi gong lessons I managed to take (before I had to stop due to overload), and now comes and goes.